Backlash, Version 2.0 Design Concept

So I have backlash! I did not know how to measure it until I posted over on the CNCZonne. It was suggested that I cut a pattern in an attempt to figure out my backlash problems.

Backlash measurement pattern.

So I cut out he piece and measured it. It turns out that I have zero backlash in the Y direction, however I have 0.0155in of backlash in the X direction. I then examined my machine and found the cause to be my lead screw nut. It seems to have significant play. I will have to make another nut and see if that eliminates my problems.

backlash test piece, two 1" squares joined together.

I also have been working on a proof of concept for my next machines linear bearings. As I said int he previous post, I recently bought 3/8" V groove bearings. I used my CNC machine to cut out two end pieces out have a cutting board to hold 3/4" aluminum square tubing. It seems that this concept will work well! The two aluminum rails are extremely parrellel, only varying from one end to the other by a few thousandths of an in! If I correct that backlash problem I have, it could be even better!

This new machine is going to be awesome!

Workbench/Plans for CNC V2.0?

So, I have moved recently and finally have built myself a proper work bench to set up my CNC machine on, instead of the floor! Check it out, it is nice!

Also, I have been working on plans for my next machine! I am planning on using 3/8" steel V-groove bearings for the linear motion system, which I just happen to win 16 of them off Ebay! I am currently working on a drawing and will post it when I have completed it. They should defiantly be better then skate-board bearings!

Fishy!

Just for fun, and to prove to my fiance that the machine could make cool things, I drew a fish in GCAM and generated the gcode. Check it out!

First Part: Arduino Prototyping Board with video!

I decided to make my first part! I recently got an Arduino Uno to start playing with and eventual use to make something cool! Anyway, I wanted a simple prototyping platform so I used GCAM to generated some gcode to cut a piece of cutting board that I could mount the Arduino on and a small prototyping board. I actually managed to cut the part with no problems on my first try! Check it out.

Precision! Kinda.

So now that I got the Dremel cutting things, I decided to test the accuracy of my machine by cutting 1in squares and circles.  I ended up cutting six circles and seven squares. The squares are surprisingly square and the circles are not quite perfect circles, but they are close. So the end result for my accuracy test:

Squares: 0.9818 +/- 0.01729 in
Circles:  0.9720 +/- 0.02246 in

 

I might be able to compensate somewhat with software. I can guarantee that my 1/8" end mill is cutting slightly larger then 1/8", resulting in slightly smaller squares and circles.

I used GCAM to create the G-Code for the test.

Time to make some real parts!

It's Dremel Time! (& Video)

So I mounted my Dremel 4000 to my Z-axis with some U bolts and miscellaneous pieces of aluminum extrusion. It is actually pretty ridged.

I am currently in the process of moving so it might take a while before I get up and running at my new apartment.

Video of Testing!

I borrowed my fiancee's video camera and filmed my CNC machine drawing the snowflake example in EMC2 as well as the letters "GCAM" which I made using GCAM.